THE PRESENT INVENTION relates to a harness arrangement for a seat and an inertia reel arrangement.
It is well known to provide a harness to restrain an occupant in a seat, and such arrangements are used extensively in the aircraft industry. Typical aircraft seat harnesses usually comprise a plurality of straps, for example a pair of shoulder straps passing from the seat over respective shoulders of the occupant, and a pair of waist straps passing from the seat and at least partially around the waist of the occupant from respective sides. All of the straps are typically provided with a metal lug at their ends, the lug being adapted to be releasably engaged within a quick release locking arrangement, commonly known in the art as a quick release box. It will therefore be understood that conventional aircraft seat harnesses are multi-point arrangements, comprising a number of straps which all engage within a single quick release box which is provided with actuating means which the occupant can trigger to release the plurality of straps and hence allow egress from the seat.
Conventional aircraft seat harnesses are designed to retain an occupant securely in the seat, allowing a very limited degree of movement so as to protect the occupant from injury in the event of sudden aircraft manoeuvres or crash situations. However, in certain fields of aviation, there is a need for an aircraft""s crew to be able to leave their seats and perform certain tasks once the aircraft is airborne. This is true, for example, of emergency services such as helicopter search and rescue services. In such fields, it can be necessary for a medic or winch-man to leave his seat and perform tasks away from the seat, which may involve being situated in the vicinity of an open aircraft door, or even, particularly in the case of a winch-man, involve leaning out of the aircraft. For safety and security, air crew performing such tasks are required to wear harnesses which not only securely restrain them in their seats for take off and landing, but also allow the air crew to move around relatively freely, away from their seats, to perform their necessary tasks. This is typically achieved by providing a generally conventional seat harness as described above, with pay out devices, typically in the form of conventional inertia reels, to allow the length of webbing strap to be paid out from the seat, once the aircraft is airborne and the air crew member wishes to move around the aircraft cabin.
Current designs of such harnesses attempt to provide an arrangement which is safe for crash requirements and which also allows air crew freedom to stand up and perform their tasks. A person""s body geometry alters significantly between standing and sitting positions. For example, the effective length of a human body between its abdominal region and its torso changes as a person stands up from a sitting position to a fully erect position, and hence a multiple point harness of the type described above which is tight enough to secure a seat occupant in a seat for take off and landing can become too tight and hence uncomfortable or painful when the occupant stands up to move away from the seat and perform his or her necessary tasks.
Attempts have previously been made to overcome the above mentioned technical problem, but they have generally involved providing elasticated elements to the harness which results in variable harness geometry which can be disadvantageous, particularly as it can result in the quick release box moving to an undesirable position which can again be uncomfortable and sometimes dangerous. Another problem of such known harness designs is that the security of the harness in the standing position can be compromised, because of a need to make the harness quickly removable for emergency egress.
A further problem arises from conventional harness arrangements which comprise inertia reels secured to the seat to allow the seat occupant to move away from the seat and perform his or her tasks. It is a current requirement that any seat restraint for use in civil aviation comprising a waist strap must be locked firmly with respect to the seat with no latent pay out, slack or play. Such waist straps cannot simply rely upon the locking of an inertia reel as is the case, for example, in the automotive industry.
It is an object of the present invention to provide an improved harness arrangement for a seat and an improved inertia reel arrangement.
According to a first aspect of the present invention, there is provided a harness arrangement for a seat, the arrangement comprising an occupant harness configured to be worn by an occupant of the seat, a separate seat harness securable to the seat, and means releasably to connect the seat harness to the occupant harness.
Preferably, the seat harness is configured to fit around or over at least part of the torso of the occupant when the seat harness is connected to the occupant""s harness.
Advantageously, the seat harness comprises a plurality of straps including a shoulder strap which, in use, passes from the seat over a shoulder of the occupant and a waist strap which passes from the seat around at least part of the waist of the occupant when the seat harness is connected to the occupant harness.
Conveniently, the harness arrangement comprises two waist straps, each being configured, in use, to pass from the seat partly around the waist of the occupant from respective sides of the occupant; and two shoulder straps, each being configured to pass over a respective shoulder of the occupant, when the seat harness is connected to the occupant harness.
Preferably, each strap of the seat harness is configured for connection to the occupant harness at a point in front of the occupant when the occupant is wearing the occupant harness.
Advantageously, the occupant harness is configured to fit around the abdominal area of an occupant.
Conveniently, the occupant harness is configured so as to be substantially clear of the torso of an occupant.
Preferably, the harness arrangement includes means to pay out the seat harness from the seat to enable the occupant to move away from the seat.
Conveniently, the means to pay out comprises at least one spring loaded pay out device, which is preferably an inertia reel connected to the seat harness.
Advantageously, the means to pay out includes locking means to selectively lock the seat harness with respect to the seat.
According to a second aspect of the present invention, there is provided a spring loaded pay out arrangement for controlled pay out of a tether line, the arrangement comprising a spring loaded pay out reel on which a tether line is wound; and locking means configured to engage the tether line at a position spaced from the would line on the reel to prevent pay out of the tether line from the inertia reel independently of the inertia reel mechanism.
Preferably, the locking means is configured to engage the tether line at a predetermined point along the length of the tether line.
Advantageously, the predetermined point along the length of the tether line is defined by a locking element fixed to the tether line.
Conveniently, the locking means comprises a locking member configured to engage the locking element to prevent movement of the locking element past the locking member in a pay out direction.
Advantageously, the locking means is arranged to allow substantially unrestricted movement of the locking element past the locking member in a direction opposite to the pay out direction.
Conveniently, the locking member is mounted for pivotal movement.
Preferably, the locking member is biased towards the tether line.
Conveniently, the tether line is selected as one of the group consisting of: a strap, a cord and webbing.
Advantageous, the tether line is wound on the reel as a coil.
Conveniently, the spring loaded pay out reel is an inertia reel.
Preferably, a harness arrangement as defined above is provided with means to pay out the seat harness from the seat, the means to pay out comprising at least one inertia reel device as defined above.